Apparatus for continuously vulcanizing rubber strip material



Nov. 28, 1950 Filed Aug. 16, 1947 B. W. BENBOW APPARATUS FOR CONTINUOUSLY VULCANIZING RUBBER STRIP MATERIAL 4 Sheets-Sheet 1 IN V EN TOR. fiur/fs W flenbow Nov. 28, 1950 B. w. BENBOW APPARATUS FOR CONTINUOUSLY VULCANIZING RUBBER STRIP MATERIAL 4 Sheets-Sheet Filed Aug. 16, 1947 E rM-HHHH I INVENTOR. fiur/is 1M fienbow Nov. 28, 1950 B. w. BENBOW APPARATUS FOR CONTINUOUSLY VULCANIZING RUBBER STRIP MATERIAL Filed Aug. 16, 1947 4 Sheets-Sheet 3 N mm ww l INVENTOR. I fiur/is Wflc'nbon/ BY ATTORNYj Nov. 28, 1950 W. BEN BOW APPARATUS FOR CONTINUOUSLY VULCANIZING RUBBER STRIP MATERIAL 4 Sheets-Sheet 4 Filed Aug. 16, 1947 INVENTOR.

50/795 M/ file/760w flTTOR/VE Y5 Illllllnhll my w m 3 Patented Nov. 28, 1950 UNITED STATES ATENT OFFICE APPARATUS FOR CONTINUOUSLY VULCAN- IZING RUBBER STRIPMATERIAL Burtis W. Benbow, Benbow, Calif.

Application August 16, 1947,.Serial No. 769,001

6 Claims. 1.

This. inventionurelates. generally to machines forcontinuously molding products. as; material like resilientnatural orsynthetic rubber. The present application is.a continuation in part of subjectmatter disclosed. in my co-pending application .Serial No.-.5.68,999,'filed December 20, 19%, for Molding Machine; now Patent No. 2,440,.- 59.8;andwhich-. in turn is .a continuation inpart oimyapplication Serial No. 460,512, filed October 2;;1942fnow abandoned;

Ingeneral it is an object of the present invention.to -provide.'ahmachine. capable of carrying out molding operations continuously, and which will enable quantity production of molded products. with a minimum amount .of labor.

Aiurther object. of the invention is to provide amolding machine capable of producing a .continuousinsulating sheath of the type disclosed in. my Patent No. 2 255,874.

Another object of. theinvention'is torprovide an improved machine of the above character-having means for supplyingalength of rubber stock to amolding-cavity, whereby all parts of .the cavity will be completely filled.

Further objects of. the invention; willri appear from the following description in-which the pre- .ferred .embodimentsihas. been; set tforth m detail in :conjunction with the accompanying drawing.

Referring: to. "the drawing:

FigureslA and 3113, taken together from left toright, illustrate the'machine in side elevation.

Figure 2 .is an end-elevation showing meanslfor adjusting the-tension upon'the endless metal belt employed.

Figure -3 is an enlarged detail illustrating means for oscillating the wire as-it is sent to the molding cavity.

Figure 4 is a plan view, on an enlarged scale, showing the nozzle means employed for feeding the rubber stock into the molding cavity.

Figure 5 is a cross-sectional, view taken along the line 5-5 of Figure 4.

Figure 6 is a cross-sectional detail taken on an enlarged scale, showing the construction of the molding wheel.

Figure? isa side elevational view, showing the upper pulley wheel of Figure 1A together with parts associated with the .same.

Figure-S is a cross-sectional detail taken along the line -8-8 of Figure 7.

Figure .9 is aidetail showing-means for operatingthe condensate valves.

Figure 10 is. an enlarged cross-sectional detail showing; one .type of rubberstoclcwhichucan be used.

Figure 11 is a side elevational view partly in sectionshowing the finished molded product.

Figure 12 is a cross-sectional view taken along the -line l2'-l2 of Fig e 11.

Figure '13 is an enlarged cross-sectional detail-showing the manner in which'the metal band serves to confine the rubber in'the molding cavity during the curing operation.

Figure 14 is a cross-sectional view taken along the line M-M 'ofFigure 13..

Figure 15' is an enlargeddetail showinga modified typewof nozzle.

Figure 16 is a detail looking toward the ex;- terior end .of. thenozzle of Figure 15 and showing thelmanner in which the nozzle is. secured to a fixed support- Figure'l'? is. an enlarged. cross-sectional detail taken along the line.ll H of Figure 15.

Figure 18 is an enlarged: cross-sectionaldetail taken'alongthe 1ine-=I8--l 8 of;Figure 15.

Figure 19'- is aside-elevational view in-section, diagrammatically illustrating the. manner. in which therubber stock isfedinto the molding cavity.

That. form of the-machine illustrated in Fig.= uresl -to-,14inclusive of the drawing consists. of a molding wheel Ill-which is rotated at a predetermined speed, and which has an endless band i! applied under tension to a portion of its periphery... A wire Or cable l2 about which the sheath is molded is applied to the molding wheel; after passing through an oscillating mechanisml3. Preformed rubber stock I4 is supplied to the molding wheel Ill, and is pressed into-the molding cavityto form a sheath of 'thedesired shape. The sheath i6 is withdrawn from the molding wheel, and after being chilled by passing through device I7, is handled in a manner to be presently described.

To describe the machine in greater detail, molding wheel l5 has suitable journals or bearing blocks 21 for journaling the same onthe main frame 22. The endless metal belt I i, which tracks upon a portion of the periphery of the molding wheel, also engages the pulley wheels 23, 24 and 25. Wheels 23- and 25 have fixed journals to the main frame, while wheel24'is journaled upon the sliding bearing blocks 21. As suitable vmeans for adjusting blocks 21, threaded rods 25} extend rearwardly from these blocks, and are engaged by nuts, which in turn are carried by the gear wheels 29. These gears are engaged by a common. pinion 31 which in turn is operated by the hand wheel 32., Thus. by

,lution per minute.

turning this hand wheel the tension upon the endless belt Ii can be varied.

It will be noted that pulley wheels 23 and 25 are located so that the band contacts the periphery of wheel ii! over an arc of the order of 270". This leaves a portion of the wheel available for introducing the rubber stock and the wire, and for removing the finished product.

The rim or peripheral portion of the molding wheel is made so that it can be heated to a desired temperature, and so as to provide cavities of the desired contour. As shown in Figure 6 a series of parallel molding cavities can be formed by machining the main rim of the wheel to receive a series of rings 37, 38, 39 and 46. In

the final assembly these rings can be permanently attached to the body of the wheel, as by welding, or they may be made replaceable by utilizing clamping screws 4| or like clamping devices for retaining the rings in place. The rings in this instance are proportioned to form a series of laterally spaced grooves or molding cavities 42, with a series of spaced teeth 43 within each cavity. (Figures 13 and 14). It is desirable to have adjacent teeth connected by a shallow rib 44, and to have the ends of the teeth grooved as indicated at 45 to seat the wire I2.

Heating of the rim may be by use of electrical elements, but in the construction illustrated it is carried out by steam.- Thus the rim of the wheel is shown provided with a steam chamber or cavity 46 (Figure 6) which is connected at spaced points with radial steam pipes 41'. These pipes connect with the'hub 48 and duct 50 of the wheel and communicate with the steam supply pipe 49.

This pipe can connect to a suitable source of steam through a pressure regulator 5|. The steam chamber in the wheel is also connected with condensate exhaust pipes 52 which lead to the opposite end of the wheel hub 48, whereby condensate is discharged through the hub duct 53. (Figure 6). In order to control removal of the condensate at periodic intervals, each pipe 52' is provided with a valve 54 having an operating stem 56 adapted to be depressed to permit flow of condensate. Mounted upon a lever there is a cam wheel 5'! (Figure 9) located within the path of movement of each operating stem 56, so that as the valves pass this wheel they are momentarily operated to permit discharge of Each valve is operated when its The drive means for the main molding wheel and the associated pulley wheel can vary in construction, but preferably it is capable of operating at two speeds. The drive means illustrated employs two electric motors 59 and 65. Motor 59 has a belt drive to shaft 6i, which extends from the speed reduction gearing 62. Pinion 53 of this gearing engages a gear 64, which is attached to the shaft of the molding wheel i 0. Motor 60 is belted to a separate speed reduction gearing 66, which has a shaft 51 aligned with shaft 6!, and adapted to be connected to the same by the manual releasable clutch 63. Motor 59 and its asso ciated drive elements can be adapted to drive the molding wheel at a speed suitable for use in setting up the machine, such as about revolution per minute, and motor 6!! can be used to secure an operating speed such as about 0.1 revo- When using motor 51 motor 59 has its belt drive disconnected, and clutch E8 is engaged.

During the molding of a continuous insulating sheath of the type to be presently described, wire [2 must be accurately seated upon the ends of the teeth 43 substantially as shown in Figures 13 and 14. Generally the wire is of substantial dimensions, such as for example from to of an inch in diameter, and therefore it is relatively stiff and resists bending. Oscillating device l3 facilitates proper positioning of this wire upon the ends of teeth (53. It consists of a roller H provided with grooves 12, to accommodate a plurality of wires 42. This roller is rotatably mounted upon a shaft, the ends of which have pivotal connections 13 with the oscillating arms 14, 16. The upper ends of these arms are cross connected by links 11. The lower ends have pivotal connections 78 with a bracket E9 which in turn is attached to the frame of the machine. Arm 14 has a lateral extension 8! which is attached to the upper end of a rod 82. The lower end of rod 82 has a pivotal connection 83 with the lever 84 (Figure 1B). One end of this lever has a pivotal mounting 86 to the frame of the machine, and the other end has a pivotal connection 81 with the link 88. The lower end of link 88 is journaled to a crank arm 89, driven at a proper rate by the motor 9!. While the rate of oscillation can vary, in practice good results have been secured with about 2 to 4 oscillations per minute with the molding wheel rotating at about 0.1 R; P. M. As shown in Figures 13 and 3 the wire 42 is applied to the machine under tension, and is caused to pass under roller ii in engagement with one of the grooves 72. The amplitude of oscillation can likewise vary, but in practice good results have been secured with an amplitude of about 2 inches, where the roller II is disposed about 20 inches from the region where the wire is engaging the teeth 43. This arrangement is suitable for wire ranging from say ,4; to of an inchin diameter. With respect to the speed of rotation of the molding wheel (which in the foregoing example was about 0.1 revolution per minute) it should be correlated with the oscillating movement so that after the wire contacts a tooth it is given more than one complete oscillation before it is caused to contact a succeeding tooth.. Thus as the wire approaches and is seated upon a tooth 43 it has slight oscillating movement in a lateral direction, which thereby insures proper and accurate seating upon the curved or concave surfaces 45.

As previously mentioned the finished sheath [6 is caused to pass through chilling means H, which can simply consist of a suitable box provided with means within the same for spraying water upon the sheath. Thereafter the sheath can pass to a suitable slitting mechanism which serves to cut the sheath along its back side, whereby the sheath can be stripped from the inner wire. The wire is then looped over a convenient idler pulley and returned to the machine.

In order to properly locate the rubber stock upon the periphery of wheel 23, an arcuat supporting bracket [8| is provided and attached to this bracket are the spacing and guide pins I02. The

.fInv-the *embo'dimentdescribed above ya special isfeed'means in the form of ainozzleas illustrated in Figures l and 5 is. utilized-for feedingthe' rubeber'stock into the molding cavity. Thismeans makes use ofra plurality of spaced paralleliplates -IIJ6,-which are carried 'by'the "fixed bracket. bar I01, and which are adapted to bepoSitionedbetween adjacent'lengths of rubber stock. :iIn addition to-such *platesyin'this instance .thexnoz'zle "-zfmakes useiof pivot pins or shafts-I28; I'DSt-and' II I! whichiextend throughthe plates/Sand serve'to .t' journal 'a series of special wheels sand rollers. .D'Fhus each shaft I68? and 'I I2 carrieswheels III Sand thesmallerrollers H2. DPint I89 carries the :rol1ers-II 'The 'groupingiof these wheels and .rollerscan be seen from Figure 4, and is the =rsame 'for the spaceibetweeneach pair of plates .z 'l'flfi. .Thus each wheel'III is located between'a pair of rollers I I2, and rollers II3 arealigned "withthercllers II2. All ofthe'small rollers are :provided with grooved'peripheries. 'Wheels II I,"

"are formed to extend within the groove 96ofthe :rrubber stock. Rollers H2, I I3" engage :the' iend izfaces of the'stock' portions QL'and together with wheels I I I' they serve'to press the-'stock a'gainst theendless metal band II, which" at?that time is interposed between the rubber stock? and theperiphery of the pulley Wheel 23. As a result," the TIStOCk is urged or crowded toward the z molding cavity in the direction of its length, due to'the I fact "that the velocity of the surface'of thebelt I I, 'in'the zone where the rubberstock'is urged *iagainst'the same, is slightly gre'aterithanthe rate with'which'the stock can be'sup'plied to the cavtity,'thus causing a slight slippage. It is-valso desirable to have the edgesurfaces 'IE!6a and- IIltb "0f plates I65 curved as illustrated whereby they f are normally disposed in closeproximity to lthe metal band I I and the periphery of the molding "iwheel.

iFiguresll and 12 illustrate a typical finished sheath. It has an accurately located-passage l2l I extending longitudinally of the a same, which is adapted.to receive a trolley wire or cable. The iback side of the sheath is slit as indicated at I22, whereby the sheath can be 'distorted ior applicai'tiOIl to a trolley wire. After such application ":suitable clamping means canine-applied to retain the slot I22 closed during normal use. The other side of the sheath is provided with regularly spaced recesses I23 separated by the gear-like teeth I2 3. The conducting teeth of a traveling contacting device are adapted to enter recesses I23 for the purpose of makingelectrical engage- -'ment with the trolley wire.

"Operation of the machine as a whole can be reviewed as follows: A length of rubber stock isselected, such as the form shown in Figure 10, and of a material which will readily cure under heat "and pressure to form a final resilient molded body. "In placing the machine in operationthemolding *Wheel IE! and the associated pulley Wheels and the endless metal band I I are driven at a suitable constant speed, and the rim of the molding wheel is heated to a suitable temperature for curing the "rubber stock. The strip I-l of rubber stock is fed J into the machine from a reel or roll of the mate rial as previously mentioned, and over thepulley wheel 23 upon the belt II. In a region adjacent the line of centers between the pulley-wheel 23 an'dlthe molding wheel III, the rubber stock enters 'TLthBLST-fI-IedTIIOZZIG between:two of theiplates I06. sSpacing-betweenthese plates: is sufiicient toacc:commodaterthe rubber stock, and the spacing likewisetconforms-to the width of the associated -..mold ing:cavity. Shortly before the rubber stock :1 enters the-molding cavity it is urged againstthe eradja'cent surface of belt I I, and as previously deiscribed'this causes the stock to be urged toward the molding cavity, thus insuring flow of'stock into the cavity to completely fill all partsoi the same. Aszthe rubber stock contacts the cavity it is heated and softened to facilitate its flowunder vthepressing effect of the metal band II and the :forward .urging of the stock just described.

When therubber stock flows into the molding w-cavitythe wire I2 is already in place upon the vteeth -lli uasxhas been previously described. As utherrubber in the cavity progresses with rotation .of. the molding wheel it is subjected to heat While ebeingheld under pressure to cure the same, and --heat curing is completed by the time the finished 'sproduct; I5 is-removed over the pulley 25 (Figure .zlB). :Atth-is' time the sheath is at an elevated --.temperatureand is subject to possible elongation ewith resulting" inaccuracy in the spacing between the teeth I24. However the sheath is immediate- ...ly-chilled by passing it through the chilling de- -vice' .I'I, whereby it is set and no longer subject to ,apossibledeformation. From the chilling device 30 I? .thesheath passes to a suitable slitting device (as-previously mentioned, whereby the back side of .-the-. sheathsis .slit longitudinally and the sheath .removedzfrom theinner-wire. The wire I2 then ,passesover a'pulley and is returned continuous- -..lyto the machine.

.The modified machine illustrated in Figures 15 -tollg. inclusive employs a molding wheel I26 corresponding to thewheel Id of Figures 1 to 14 in- ..clusive,.and which is provided with two pairs of molding cavities, one pair comprising cavities I27, and the second pair the cavities I28. These cavities are formed by the assembly of a series of .rings upon the rim of wheel I26. Rings I29 form I the. endsof this assembly, rings I3I form ridges in the .molding cavity, rings I32 divide adjacent cavities,..a-nd rings I33 form a separation between the two pairsof cavities. Rings I3 3 form spaces betweeneadjacent rings. Rings I29 and I33 are provided with relatively accurately machined and cylindrically formed peripheries I36 and I31. A cavity formed in this manner will mold a continuous strip having a groove extending along one side of the same.

The feed nozzle I38 in this instance consists of the two side plates I39, and the intermediate plate "I4 I. These plates are assembled and clamped together by the bolts I 32 which are provided with suitablespacers I 13. Edge portions I45 and I45 "of 'the plates are curved. and contoured substantially as illustrated in Figure 15. Thus the sur- "faces of'ithese edge portions are in close apposition-with the adjacent surface of the metal band I I, and the outer peripheral surfaces of the rings "I29 and I33.

-As asuitablemounting for the nozzle I33, the plates I39 and Isl are provided with aligned openings- I'Iliiserving to accommodate a rigid bar Ml. This baris'attached to a rigid support, such -as -a rigid part of the machine frame. Each of the plates "I38 is also provided-with vertical and horizontal set screws M8 and M9, by means of "which the nozzle is adjustably clamped to the bar il.

As' previo-usly explained the adjustment. is

such that the surfaces of the edge portions I44 and I 45 have relatively close apposition to the adjacent surfaces of the band H and the peripheries of rings 529 and I33. Thus two spaces or passages are formed by the nozzle for receiving the rubber stock, and each space is confined on its sides by plates I39 and MI, while its upper side is confined by the exterior surface of the band H, and the lower side by the molding wheel and cavities.

The rubber stock li in this instance may have a rectangular cross-sectional contour as illustrated in Figure 18, or if desired it may be circular or oval. In any event the dimensions of this stock are sufficient to provide ample material for filling two cavities simultaneously with a speed of advancement only slightly less than the speed of movement of band H. Assuming that the rubber stock has a rectangular cross-sectional contour, it occupies a position between the plates I39 and i i! of the nozzle substantially as illustrated in Figure 18, as it initially enters the nozzle. As the stock contacts the molding wheel it is softened by heat, and simultaneously with this softening the rubber is urged by the band H into the molding cavities 21 or I28. This is made clear by reference to diagrammatic Figure 19. In the zone ifim there has been some softening of the rubber stock by an increase in its temperature, and the softened rubber stock is flowing into the molding cavity. At Hill) the rubber has completely flowed into the molding cavity and is being retained in the cavity by the endless band H. A banking effect occurs in the region new, due to the fact that the dimensions of the rubber stock tend to supply more rubber than is actually needed to fill the cavity. In this region the rubber is being confined by the plates I39 and Hi! and is being pressed into engagement with band H. This bank is desirable in that it secures optimum feeding of the rubber stock with complete filling of the molding cavities.

As shown in Figure 19, supplemental means can be provided for urging the rubber stock against the adjacent surface of the endless band ii, for the purpose of increasing the banking effect. In place of utilizing a plurality of rollers and wheels illustrated in Figures 4 and 5, I provide in this instance a, single wheel or roller I52 which is journaled upon the end of a pivoted arm 553. An adjustable tension spring I54 urges the arm 53 in a clockwise direction as viewed in Figure 19, thus urging the roller 152 against the rubber stock and thus urging the rubber stock into frictional engagement with the band H in a region in advance of the banking region. For some types of rubber stock tending to flow readily when heated, use of the roller 552 can be omit ed. However with other types of rubber stock, difficulty is encountered in securing proper filling of the cavity without the roller l 52, and in such instances use of this roller insures the maintenance of proper banking zone l5la, with proper flow of the rubber into the molding cavity to fill all portions of the same.

It will be evident from the foregoing that my machine can be employed to continuously mold a variety of products, in addition to the insulating sheath described with respect to Figures 1 to 14 inclusive. The molding cavities can be formed in accordance with the particular product desired to form, for example such products as rubber edging, window weather stripping, and the like.

I claim:

1. In a machine for continuously molding a material like rubber, a molding wheel adapted to be rotated at a predetermined rate, the wheel being provided with molding cavity. extending about its peripheral portion, a pulley mounted adjacent one side of the molding wheel, a band entrained over said pulley and molding wheel and passing between the peripheries of the pulley and the molding wheel, means for driving the wheel and pulley whereby the band progresses about the pulley, then between the pulley and the wheel and then about the wheel, a feed nozzle disposed in proximity with both the periphery of the wheel and the surface of the band in a region adjacent one side of the line of centers between the pulley and the wheel, said nozzle forming a confined space for receiving a length of rubber stock and for presenting the same under confinement to the cavity, said nozzle including a pair of plates between which the rubber stock is caused to pass, each of said plates having edge portions of the same in close apposition with the surface of the band and the outer periphery of the molding wheel, and means for supplying a length of rubber stock to said nozzle.

2. In amachine for continuously molding a material like rubber, a molding wheel adapted to be rotated at a predetermined rate, the wheel being provided with a continuous molding cavity extending about its peripheral portion, a pulley mounted adjacent one side of the molding wheel, a metal band entrained over said pulley and the molding wheel and passing between the peripheries of the pulley and the molding wheel, means for continuously driving the wheel and pulley whereby the band progresses about the pulley, then between the pulley and the wheel and then about the wheel, a feed nozzle disposed in proximity with both the peripher of the wheel and the surface of the band in a region adjacent one side of the line of centers between the pulley and the wheel, said nozzle forming a confined space for receiving a length of rubber stock and for presenting the same under partial compression to the molding cavity, said nozzle including a pair of substantially parallel plates between which the rubber stock is caused to pass, each of said plates including convergent curved edge portions in close apposition with the surface of the band and the outer periphery of the molding wheel, the spacing between the plates corresponding substantially to the width of said molding cavity, and means for supplying a length of rubber stock to said nozzle.

3. In a machine for continuously molding a material like rubber, a molding wheel adapted to be rotated at a predetermined rate, the wheel being provided with a molding cavity extending about its peripheral portion, a pulley mounted adjacent one side of the molding wheel, a band entrained over said pulley and the molding wheel and passing between the peripheries of the pulley and the molding wheel, the exterior face of that portion of the band which is entrained over the pulley being convex, means for driving the wheel and pulley whereby the band progresses about the pulley, then between the pulley and the wheel and then about the wheel, means for supplying a strip of moldable material for presentation to the molding cavity in a region adjacent the line of centers between the pulley and the wheel, and means located adjacent the point of introduction of the moldable strip into the cavity for urging the strip into frictional engagement with the adjacent convex surface of the band, whereby said strip is urged in the direction of its length toward the wheel and the molding cavity.

4. A machine as in claim 3 in which said last named means includes spaced plates between which the rubber strip is adapted to pass as the strip is urged into frictional engagement with the band.

5. A machine as in claim 3 in which said last 10 named means includes spaced plates between which the rubber strip is adapted to pass, said plates having curved convergent edge portions of the same in close apposition with the exterior convex surface of the band and with the peripheral surface of the molding wheel.

6. In a machine for continuously molding a material like rubber, a molding wheel adapted to be rotated at a predetermined rate, the wheel being provided with a molding cavity extending about its peripheral portion, a pulley Wheel mounted adjacent one side of the molding wheel, a band entrained over said pulley and the molding wheel and passing between the peripheries of surface of that portion of the band which is en- 10 trained over the pulley being convex, means for driving the wheel and pulley whereby the band progresses about the pulley, then between the pulley and the wheel and then about the wheel, means for supplying a strip of moldable material for presentation to the molding cavity in a region adjacent the line of centers between the pulley and the wheel, and means located adjacent the point of introduction of the moldable strip into the cavity for urging the strip into frictional engagement with the adjacent convex surface of said band and for guiding the strip into the cavity, said last named means including roller means engaging the strip and urging the same toward the adjacent surface of the band.

BURTIS W. BENBOW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,166,490 Gora July 18, 1939 2,303,554 Humphreys Dec. 1, 1942 

